Always ensure you have cleaned your frame with isopropyl alcohol (can be purchased from ebay or hardware or medical suppliers.) Even brand new frames have dirt and dust on them. Trim a small square of the application tape provided to lift off the peice your working on, and it will help you not touch the actual invisifilm during the application.
Spray the adhesive side of the piece your working on with water don't be stingy get it wet!
Proceed to lining up into position, and start wiping with the application tool suppled from the center outwards. Pushing the water out, and warming the area with a heat gun/hairdryer at the same time. Start with a small piece to get used to the technique. If you really wet the invisifilm you will need to check back within an hour of application with a heat source to ensure you have dried the edges and got those stuck down. If you went for the dry application with heat you wont need to worry about this.